Elementary concepts of the internet, worldwide web, software and
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The document discusses computer networks and the internet. It explains that the internet is a network of networks that connects millions of computers globally using common protocols like TCP/IP. The World Wide Web is a system that allows users to access and share information over the internet. It provides hyperlinks between documents and multimedia web pages. The web runs on a client-server model, with web servers hosting websites and web browsers on client devices accessing these sites using URLs. Overall, the internet and web provide a vast global network for sharing information and resources.
Elementary concepts of the internet, worldwide web, software and
- 1. L J Haravu
- 2. What are networks? What is the Internet and how does it work? What is the Worldwide Web (WWW)? How is it different from the Internet? What is needed to access the Web? Important Web concepts Content and services on the Internet
- 3. Whether we know it or not, we all belong to one or more networks Family – Friends – Professional – Bank – Telephone - TV - Hobby – Religious, etc., etc., Network paradigms Share and exchange data, information and knowledge Share, exchange resources Collaborate on common projects/interests Inform, entertain Computer networks are the infrastructure of the Internet
- 4. A local area network or LAN A collection of computers within a building or office so that they can inter-communicate/share data, information
- 5. Wide Area Network (WAN) Connect computers across a wide geographical area, e.g., between different branches of a company in different parts of the country
- 6. It is a Network of Networks. Millions of networks – LANs, WANs, individual devices using diverse telecom networks connect to each other. All the networks agree to use common rules to connect to each other. These rules are called protocols Protocols are based on a worldwide agreement of how to represent/exchange/transmit information. TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of protocols fundamental to the Web Internet software of all kinds conforms to the TCP/IP Let’s see a Video of how the Internet works
- 7. The Internet is the medium or container or carrier The Worldwide Web (WWW or Web) has the content The Web provides the means to store, access, communicate, retrieve information stored in millions of networks all over the world in different languages The Web is therefore also known as the Information Superhighway The Web is the intelligence behind the hardware of the Internet. The intelligence behind the Web is from human beings It is not only an information network but also a knowledge network
- 8. Depending on the need for speed of a connection (also called Bandwidth) the options are: Dial-up Slowest. Must dial-up to a phone line to connect Internet and phone cannot be used simultaneously DSL or Digital Subscriber Line Faster than Dial-up. Always on. Higher speeds of access. Telephone and Internet can be used simultaneously Cable Uses the Cable TV connection. Can be as fast as DSL, but security can be a problem Wireless
- 9. Server Client Client Client The Smart Class Facility at AVK will also be run as a Client-Server Facility
- 10. All networks including the Web are based on an architecture of Servers and Clients A Server is a special type of computer on the network that provides one or more services to clients computers on the network A Client is also a computer which users have access to on the network. The Client seeks services from the Server and the Server provides the services.
- 11. File Server Database Server Email Server Web Server Internet Remote Client
- 12. There are dedicated servers that are generally owned by a web service provider, e.g., AVKs web site is located on a web server in the US provided by a company called GoDaddy Web Servers are up and running 24 x 7 x 365 days The Web Service Provider also called Hosting provider provides the space, the software and maintenance of the site, security of data There are different types of servers: file, database, application, e-mail, etc.
- 13. Every site belongs to a domain, e.g., the schools domain name is acharyavidyakula.org. The School pays to own this domain name A page on the web site has an address called the URL (Universal Resource Locator) e.g., the URL for the Schools web site is http://www.acharyavidyakula.org) Once you know the URL of web sites/pages, these can be accessed with software known as a web browser, e.g., Internet Explorer, Firefox
- 14. The fundamental constituent of the Web is a page Pages that you see on a site are represented using a language called HTML (hypertext markup language) An HTML page can have text, symbols, images, video in it, e.g., http://www.acharyavidyakula.org/web/home Not all pages of a site are static. Some of them are created dynamically
- 15. The Process A client machine connects to the Internet Once connected, it requests a web site/page by entering the URL in a browser The request passes through a maze of routers, switches, cables, satellite, cell phone towers, etc., and until it reaches the Web server The Web Server which is always ‘listening’ to requests, receives the request. It knows the address from where the request was received The Web Server returns the page requested to the client by its address Software on the client computer displays the page
- 16. An important element of most web pages is hypertext. This is specially formatted text. The hypertext is meant to connect the user to another page in the same site or to a page in some other site. The link is called a hyperlink. Let’s see an example Hyperlinks can link to text, images, videos on one or more web sites/pages Some web pages have forms that can be filled Many web pages have a search box, e.g., Google
- 17. The Web is undoubtedly a veritable mine or repository of information. The following are a few of the types of sites/content available: Simple textual pages Pages with more than just textual content Database sites on various subjects Email providers, e.g., gmail, yahoo, rediffmail Sites of companies, banks, institutions, schools, governments, international organizations, universities, charitable organizations, etc., etc. Library sites, e.g., SDM-IMD, Mysore
- 18. Digital libraries, e.g., The Hathi Trust, Google Books Search engine sites, e.g., Google, Bing, Yahoo Sellers, resellers of goods and services, e.g. Amazon, Ebay – these are interactive sites Travel Services such as travel agents, airline and railway reservations, e.g., the reservation site for Indian Railways Reference Materials such as Encyclopedia’s, dictionaries, directories Learning resources Courseware sites, e.g., MIT Open Courseware
- 19. Scholarly subject portals, e.g., University of California Tutorial Sites on different subjects, e.g., Health Blogs Wikis of different kinds The best example of a WIKI is Wikipedia Music sites to listen/download music, e.g., MusicIndiaonline Photo publishing/sharing/downloading sites Videos/Movies publishing/sharing/downloading sites, e.g., Youtube Social networking sites, e.g., Facebook
- 20. Exchange electronic mail (E-mail) with friends and colleagues with accounts on the Internet Post information for others to access, and update it frequently Search many types of general and specialized databases Access and use many services online, e.g., railway reservations, e-banking Access/exchange multimedia information: audio, photographic images and video, and Be part of an online social network, e.g., Facebook, etc., etc., As a source of Infotainment As a source of knowledge (experience exchange) access diverse perspectives from around the world.
- 21. The Web is a bad influence on children Prevent children from using the Internet Workers waste time during office hours with the Internet The Web has made us stupid. We only copy and paste and feel very great about it.